Push button



FIG. 1 is a front isometric view of a push button in accordance with the new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a left side elevation view thereof, a right side elevation view being mirror image thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken lines shown in FIGS. 1, 2 and 6 represent the bounds of the claimed design, with the lines themselves and the areas within them forming no part of the claimed design. 

The ornamental design for a push button, as shown and described. 